willo Member 9 Member For: 19y 2m Posted 09/10/06 02:56 AM Share Posted 09/10/06 02:56 AM Has any one come across any problems with there Speedo on there BA, Got booked at 118km on cruise control on 100km?? Link to comment Share on other sites More sharing options...
Turbo6man Lifetime Members 4,084 Member For: 22y 2m 16d Gender: Male Location: South Coast NSW Posted 09/10/06 03:01 AM Share Posted 09/10/06 03:01 AM You better get along to your Ford dealer real quick because if that is true their WDS will be able to verify it for you (giving you a defence at court) and they will also be able to correct the problem.Personally I have never seen one to be more than 4% in error so maybe the radar unit or whatever you were speed checked with is out of whack or the nice policeman is simply telling porkies because he doesn't like your car or his missus ran off with a guy in an XR6T??? Link to comment Share on other sites More sharing options...
willo Member 9 Member For: 19y 2m Posted 09/10/06 03:07 AM Author Share Posted 09/10/06 03:07 AM the nice policeman you speak of was the biggest D*Ck I've ever come across, had me on the side of the road for over an hour for a speeding fine, went all over my car, searched me and my girl friend. I could not believe it Link to comment Share on other sites More sharing options...
tmac450 Member 1,650 Member For: 18y 3m 22d Gender: Male Location: NSW Posted 09/10/06 03:07 AM Share Posted 09/10/06 03:07 AM Most speedos read under. My GPS reads 92 when the speedo is at 100. Link to comment Share on other sites More sharing options...
Turbo6man Lifetime Members 4,084 Member For: 22y 2m 16d Gender: Male Location: South Coast NSW Posted 09/10/06 03:27 AM Share Posted 09/10/06 03:27 AM Most speedos read under. My GPS reads 92 when the speedo is at 100.←That is quite incorrect. MOST speedos read over, but usually by no more than 3%-4% if you are running the factory wheel. So when the speedo is showing 100 your true speed may be something like 96 or 97.Even if you were to change wheels it would be a very rare occurence for a speedo to read under - you would have to use a very much larger wheel/tyre combo to have this outcome. Link to comment Share on other sites More sharing options...
willo Member 9 Member For: 19y 2m Posted 09/10/06 03:30 AM Author Share Posted 09/10/06 03:30 AM Had factory 17's now have 20' rims Link to comment Share on other sites More sharing options...
tab Sucker Moderating Team 32,303 Member For: 20y 8m 1d Gender: Male Location: Brisbane Posted 09/10/06 03:47 AM Share Posted 09/10/06 03:47 AM Has the PCM been re-calibrated by Ford since you changed the rims? Link to comment Share on other sites More sharing options...
turbotom Team Bute Donating Members 1,550 Member For: 21y 5m 11d Gender: Male Location: Adelaide Posted 09/10/06 04:16 AM Share Posted 09/10/06 04:16 AM Looks to me like your 20" wheel circumference might be greater than the factory 17" circumference (roll out) This will mean that you are travelling faster than what you would be travelling at on std 17" tyres at the same indicated speed.When doing my interstate runs, I set my cruise control, and then time the period between the km markers on a straight section of road.A lot of watches have a tachymeter scale around the rim to determine speed in this fashion.Otherwise, divide 3600 by the time it takes to travel that 1 km (in seconds) to calculate the speed in kph....eg... 35 seconds to travel 1 km...3600 / 35 = 102.86 kphThis is a crude method, and relies on the km markers to be accurate, and your ability to start/stop the watch reliably.Do it several times on different markers, or average the time over 5 km to get better reliability.This might give you some idea of how far out your speedo is before you start disputing the fine.cheerstom Link to comment Share on other sites More sharing options...
tmac450 Member 1,650 Member For: 18y 3m 22d Gender: Male Location: NSW Posted 09/10/06 04:20 AM Share Posted 09/10/06 04:20 AM Most speedos read under. My GPS reads 92 when the speedo is at 100.←That is quite incorrect. MOST speedos read over, but usually by no more than 3%-4% if you are running the factory wheel. So when the speedo is showing 100 your true speed may be something like 96 or 97.Even if you were to change wheels it would be a very rare occurence for a speedo to read under - you would have to use a very much larger wheel/tyre combo to have this outcome.←Did you read all of what I said or just the first bit? Maybe I should have said over, but I said that the GPS reads 92 when the speedo says 100, exactly the same as what you said. I agree on the wheels as the rolling diameter would have to change a fair bit. Link to comment Share on other sites More sharing options...
Iconic Bionic My engine bay is Bionic Donating Members 3,726 Member For: 18y 9m 7d Gender: Male Location: Freeways Posted 09/10/06 05:25 AM Share Posted 09/10/06 05:25 AM Has any one come across any problems with there Speedo on there BA, Got booked at 118km on cruise control on 100km??←What state did you get stopped in?Secondly, my GPS reads precisely with my BF speedo. Although both are not highly accurate, they always read the same. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now